d2d-repeating-gradients.patch

From: Robert O'Callahan <robert@ocallahan.org>
Bug 768775. Improve the precision of the calculation of the number of stops that need to be added to handle 'repeat' and 'reflect', when we're filling a path. r=bas

diff --git a/gfx/cairo/cairo/src/cairo-d2d-surface.cpp b/gfx/cairo/cairo/src/cairo-d2d-surface.cpp
--- a/gfx/cairo/cairo/src/cairo-d2d-surface.cpp
+++ b/gfx/cairo/cairo/src/cairo-d2d-surface.cpp
@@ -1411,17 +1411,17 @@ static RefPtr<ID2D1Brush>
 
 	gradient_center.x = _cairo_fixed_to_float(source_pattern->c1.x);
 	gradient_center.y = _cairo_fixed_to_float(source_pattern->c1.y);
 
 	// Transform surface corners into pattern coordinates.
 	cairo_matrix_transform_point(&source_pattern->base.base.matrix, &top_left.x, &top_left.y);
 	cairo_matrix_transform_point(&source_pattern->base.base.matrix, &top_right.x, &top_right.y);
 	cairo_matrix_transform_point(&source_pattern->base.base.matrix, &bottom_left.x, &bottom_left.y);
-	cairo_matrix_transform_point(&source_pattern->base.base.matrix, &bottom_right.x, &top_left.y);
+	cairo_matrix_transform_point(&source_pattern->base.base.matrix, &bottom_right.x, &bottom_right.y);
 
 	// Find the corner furthest away from the gradient center in pattern space.
 	double largest = MAX(_cairo_d2d_point_dist(top_left, gradient_center), _cairo_d2d_point_dist(top_right, gradient_center));
 	largest = MAX(largest, _cairo_d2d_point_dist(bottom_left, gradient_center));
 	largest = MAX(largest, _cairo_d2d_point_dist(bottom_right, gradient_center));
 
 	unsigned int minSize = (unsigned int)ceil(largest);
 
@@ -1531,16 +1531,17 @@ static RefPtr<ID2D1Brush>
 					   stopCollection,
 					   &brush);
     delete [] stops;
     return brush;
 }
 
 static RefPtr<ID2D1Brush>
 _cairo_d2d_create_linear_gradient_brush(cairo_d2d_surface_t *d2dsurf,
+					cairo_path_fixed_t *fill_path,
 					cairo_linear_pattern_t *source_pattern)
 {
     if (source_pattern->p1.x == source_pattern->p2.x &&
 	source_pattern->p1.y == source_pattern->p2.y) {
 	// Cairo behavior in this situation is to draw a solid color the size of the last stop.
 	RefPtr<ID2D1SolidColorBrush> brush;
 	d2dsurf->rt->CreateSolidColorBrush(
 	    _cairo_d2d_color_from_cairo_color_stop(source_pattern->base.stops[source_pattern->base.n_stops - 1].color),
@@ -1564,35 +1565,46 @@ static RefPtr<ID2D1Brush>
     p1.x = _cairo_fixed_to_float(source_pattern->p1.x);
     p1.y = _cairo_fixed_to_float(source_pattern->p1.y);
     p2.x = _cairo_fixed_to_float(source_pattern->p2.x);
     p2.y = _cairo_fixed_to_float(source_pattern->p2.y);
 
     D2D1_GRADIENT_STOP *stops;
     int num_stops = source_pattern->base.n_stops;
     if (source_pattern->base.base.extend == CAIRO_EXTEND_REPEAT || source_pattern->base.base.extend == CAIRO_EXTEND_REFLECT) {
-
-	RefPtr<IDXGISurface> surf;
-	d2dsurf->surface->QueryInterface(&surf);
-	DXGI_SURFACE_DESC desc;
-	surf->GetDesc(&desc);
-
 	// Get this when the points are not transformed yet.
 	double gradient_length = _cairo_d2d_point_dist(p1, p2);
-
-	// Calculate the repeat count needed;
-	cairo_point_double_t top_left, top_right, bottom_left, bottom_right;
-	top_left.x = bottom_left.x = top_left.y = top_right.y = 0;
-	top_right.x = bottom_right.x = desc.Width;
-	bottom_right.y = bottom_left.y = desc.Height;
+        cairo_point_double_t top_left, top_right, bottom_left, bottom_right;
+
+        if (fill_path) {
+            // Calculate the repeat count needed;
+            cairo_box_t fill_extents;
+            _cairo_path_fixed_extents (fill_path, &fill_extents);
+
+	    top_left.x = bottom_left.x = _cairo_fixed_to_double (fill_extents.p1.x);
+	    top_left.y = top_right.y = _cairo_fixed_to_double (fill_extents.p1.y);
+	    top_right.x = bottom_right.x = _cairo_fixed_to_double (fill_extents.p2.x);
+	    bottom_right.y = bottom_left.y = _cairo_fixed_to_double (fill_extents.p2.y);
+        } else {
+            RefPtr<IDXGISurface> surf;
+            d2dsurf->surface->QueryInterface(&surf);
+            DXGI_SURFACE_DESC desc;
+            surf->GetDesc(&desc);
+
+            top_left.x = bottom_left.x = 0;
+            top_left.y = top_right.y = 0;
+            top_right.x = bottom_right.x = desc.Width;
+            bottom_right.y = bottom_left.y = desc.Height;
+        }
+
 	// Transform the corners of our surface to pattern space.
 	cairo_matrix_transform_point(&source_pattern->base.base.matrix, &top_left.x, &top_left.y);
 	cairo_matrix_transform_point(&source_pattern->base.base.matrix, &top_right.x, &top_right.y);
 	cairo_matrix_transform_point(&source_pattern->base.base.matrix, &bottom_left.x, &bottom_left.y);
-	cairo_matrix_transform_point(&source_pattern->base.base.matrix, &bottom_right.x, &top_left.y);
+	cairo_matrix_transform_point(&source_pattern->base.base.matrix, &bottom_right.x, &bottom_right.y);
 
 	cairo_point_double_t u;
 	// Unit vector of the gradient direction.
 	u = _cairo_d2d_subtract_point(p2, p1);
 	_cairo_d2d_normalize_point(&u);
 
 	// (corner - p1) . u = |corner - p1| cos(a) where a is the angle between the two vectors.
 	// Coincidentally |corner - p1| cos(a) is actually also the distance our gradient needs to cover since
@@ -1701,17 +1713,18 @@ static RefPtr<ID2D1Brush>
  * \param d2dsurf Surface to create a brush for
  * \param pattern The pattern to create a brush for
  * \param unique We cache the bitmap/color brush for speed. If this
  * needs a brush that is unique (i.e. when more than one is needed),
  * this will make the function return a seperate brush.
  * \return A brush object
  */
 static RefPtr<ID2D1Brush>
-_cairo_d2d_create_brush_for_pattern(cairo_d2d_surface_t *d2dsurf, 
+_cairo_d2d_create_brush_for_pattern(cairo_d2d_surface_t *d2dsurf,
+				    cairo_path_fixed_t *fill_path,
 				    const cairo_pattern_t *pattern,
 				    bool unique = false)
 {
     HRESULT hr;
 
     if (pattern->type == CAIRO_PATTERN_TYPE_SOLID) {
 	cairo_solid_pattern_t *sourcePattern =
 	    (cairo_solid_pattern_t*)pattern;
@@ -1729,17 +1742,17 @@ static RefPtr<ID2D1Brush>
 		d2dsurf->solidColorBrush->SetColor(color);
 	    }
 	    return d2dsurf->solidColorBrush;
 	}
 
     } else if (pattern->type == CAIRO_PATTERN_TYPE_LINEAR) {
 	cairo_linear_pattern_t *source_pattern =
 	    (cairo_linear_pattern_t*)pattern;
-	return _cairo_d2d_create_linear_gradient_brush(d2dsurf, source_pattern);
+	return _cairo_d2d_create_linear_gradient_brush(d2dsurf, fill_path, source_pattern);
     } else if (pattern->type == CAIRO_PATTERN_TYPE_RADIAL) {
 	cairo_radial_pattern_t *source_pattern =
 	    (cairo_radial_pattern_t*)pattern;
 	return _cairo_d2d_create_radial_gradient_brush(d2dsurf, source_pattern);
     } else if (pattern->type == CAIRO_PATTERN_TYPE_SURFACE) {
 	cairo_matrix_t mat = pattern->matrix;
 	cairo_matrix_invert(&mat);
 
@@ -3228,17 +3241,17 @@ static cairo_int_status_t
 
 	if (unlikely(status))
 	    return status;
     }
 #endif
 
     target_rt->SetAntialiasMode(D2D1_ANTIALIAS_MODE_ALIASED);
 
-    RefPtr<ID2D1Brush> brush = _cairo_d2d_create_brush_for_pattern(d2dsurf,
+    RefPtr<ID2D1Brush> brush = _cairo_d2d_create_brush_for_pattern(d2dsurf, NULL,
 								   source);
     
     if (!brush) {
 	return CAIRO_INT_STATUS_UNSUPPORTED;
     }
 
     D2D1_SIZE_F size = target_rt->GetSize();
     target_rt->FillRectangle(D2D1::RectF((FLOAT)0,
@@ -3349,17 +3362,17 @@ static cairo_int_status_t
 							    source->filter,
 							    solidAlphaValue);
 	    if (rv != CAIRO_INT_STATUS_UNSUPPORTED) {
 		return rv;
 	    }
 	}
     }
 
-    RefPtr<ID2D1Brush> brush = _cairo_d2d_create_brush_for_pattern(d2dsurf, source);
+    RefPtr<ID2D1Brush> brush = _cairo_d2d_create_brush_for_pattern(d2dsurf, NULL, source);
     if (!brush) {
 	return CAIRO_INT_STATUS_UNSUPPORTED;
     }
 
     RefPtr<ID2D1RenderTarget> target_rt = d2dsurf->rt;
 #ifndef ALWAYS_MANUAL_COMPOSITE
     if (op != CAIRO_OPERATOR_OVER) {
 #endif
@@ -3389,17 +3402,17 @@ static cairo_int_status_t
 	brush->SetOpacity(1.0);
 
 	if (target_rt.get() != d2dsurf->rt.get()) {
 	    return _cairo_d2d_blend_temp_surface(d2dsurf, op, target_rt, clip);
 	}
 	return CAIRO_INT_STATUS_SUCCESS;
     }
 
-    RefPtr<ID2D1Brush> opacityBrush = _cairo_d2d_create_brush_for_pattern(d2dsurf, mask, true);
+    RefPtr<ID2D1Brush> opacityBrush = _cairo_d2d_create_brush_for_pattern(d2dsurf, NULL, mask, true);
     if (!opacityBrush) {
 	return CAIRO_INT_STATUS_UNSUPPORTED;
     }
 
     if (!d2dsurf->maskLayer) {
 	d2dsurf->rt->CreateLayer(&d2dsurf->maskLayer);
     }
     target_rt->PushLayer(D2D1::LayerParameters(D2D1::InfiniteRect(),
@@ -3475,17 +3488,17 @@ static cairo_int_status_t
 									     D2D1_FIGURE_BEGIN_FILLED);
     
     bool transformed = true;
 
     if (_cairo_matrix_is_identity(ctm)) {
       transformed = false;
     }
 
-    RefPtr<ID2D1Brush> brush = _cairo_d2d_create_brush_for_pattern(d2dsurf,
+    RefPtr<ID2D1Brush> brush = _cairo_d2d_create_brush_for_pattern(d2dsurf, NULL,
 								   source);
     if (!brush) {
 	return CAIRO_INT_STATUS_UNSUPPORTED;
     }
 
     D2D1::Matrix3x2F mat;
     if (transformed) {
       // If we are transformed we will draw the geometry multiplied by the
@@ -3602,31 +3615,31 @@ static cairo_int_status_t
     }
 
     if (is_box) {
 	float x1 = _cairo_fixed_to_float(box.p1.x);
 	float y1 = _cairo_fixed_to_float(box.p1.y);    
 	float x2 = _cairo_fixed_to_float(box.p2.x);    
 	float y2 = _cairo_fixed_to_float(box.p2.y);
 	RefPtr<ID2D1Brush> brush = _cairo_d2d_create_brush_for_pattern(d2dsurf,
-								       source);
+	    path, source);
 	if (!brush) {
 	    return CAIRO_INT_STATUS_UNSUPPORTED;
 	}
 
 	target_rt->FillRectangle(D2D1::RectF(x1,
 					     y1,
 					     x2,
 					     y2),
 				 brush);
     } else {
 	RefPtr<ID2D1Geometry> d2dpath = _cairo_d2d_create_path_geometry_for_path(path, fill_rule, D2D1_FIGURE_BEGIN_FILLED);
 
 	RefPtr<ID2D1Brush> brush = _cairo_d2d_create_brush_for_pattern(d2dsurf,
-								       source);
+            path, source);
 	if (!brush) {
 	    return CAIRO_INT_STATUS_UNSUPPORTED;
 	}
 	target_rt->FillGeometry(d2dpath, brush);
     }
 
     if (target_rt.get() != d2dsurf->rt.get()) {
 	double x1, y1, x2, y2;
@@ -4138,17 +4151,17 @@ static cairo_int_status_t
 					DWRITE_TEXTURE_ALIASED_1x1 : DWRITE_TEXTURE_CLEARTYPE_3x1,
 					&bounds);
 	fontArea.x = bounds.left;
 	fontArea.y = bounds.top;
 	fontArea.width = bounds.right - bounds.left;
 	fontArea.height = bounds.bottom - bounds.top;
     }
 
-    RefPtr<ID2D1Brush> brush = _cairo_d2d_create_brush_for_pattern(dst,
+    RefPtr<ID2D1Brush> brush = _cairo_d2d_create_brush_for_pattern(dst, NULL,
 								   source);
 
     if (!brush) {
 	return CAIRO_INT_STATUS_UNSUPPORTED;
     }
     
     if (transform) {
 	D2D1::Matrix3x2F mat_inverse = _cairo_d2d_matrix_from_matrix(&dwritesf->mat_inverse);